Valve control for presses and the like



May 22, 194-5. I s v 2,376,519

' 'VALVE CONTROL FOR PRESSES AND THE LIKE Fild July 29,, 1945 INVENTOR VThogzas 7'? 320g ATTORNEYS i Patented May 22, 1945 2,378,519 VALVECONTROL FOR PBESSES AND THE LIKE Thomas F. Stacy, Plqua, Ohio, asslgnorto The FrenchOll Mill Machinery Company, Plqna,

Ohio

Application July 29, 1943, Serial No. 496,602 8 Claims. (01.121-38) uldunder pressure which is delivered to and ex- This invention relates toimprovements in operating or control valve mechanisms for fluid--pressure-actuated presses and the like, a primary purpose of myinvention being to provide a valve mechanism adapted to effect a veryhigh speed of operation of the press with the use of the minimum volumeof pressure fluid in order to conserve pressure fluid and avoid thenecessity for maintaining or pumping a large quantity thereof.

Another object of the invention is to provide an eflicient, practicaland desirable operating or control valve mechanism for presses and thelike which is of novel, improved construction; which is adapted toeffect a rapid initial movement of the press ram or movable member withthe minimum use of pressure fluid, and then increase the operatingpressure on the press ram or member when it encounters apredeterminedresistance to its movement, and a rapid return or pull-backmovement of the press ram or member.

Further objects and advantages of the invention will appear from thefollowing specification of the preferred embodiment of the invention,shown in the accompanying drawing, and the novel features of theinvention are set forth in the appended claims.

In said drawing, the flgure is a schematic view, artly in section, of apress operating valve mechanism embodying the invention, showing bysolid lines the positions occupied bythe parts during the initial rapidportion of the work stroke of the press ram before the maximum pressureis applied; and indicating by broken lines the positions of the movablevalve elements for the application of maximum pressure'and for thepull-back or return movement of the press ram.

Referring to the drawing, l represents astatio'nary member or cylinderand II the movable ram piston or member of a press actuated by hydraulicor fluid pressure. ,The chamber II, or portion of the cylinder at oneside or end of the piston, constitutes tile work chamberin which thepressure acts on the larger area of this end face of the pistonforproducing the work stroke of the piston, and the cylinder chamber l3 'atthe opposite side or end of the piston forms a pullback chamber l3 inwhich the pressure acts,

against the other end face of the piston, which is of smaller area, topull back or return the piston or movable press member. The work andpullback chambers are shown as chambers in a single cylinder, but theinvention is not restricted to this form of pressure actuating means forthe movable press ram or member.

l5 represents an accumulator or source of liqhausted from the presschambers l2 and I3 for operating the press under the control of a valveor device A and valves B and C, which, for con venience of description,are herein respectively designated the operating valve, the main controlvalve and the auxiliary control valve. The main and auxiliary valves Band C control the passages ofthe pressure fluid to and from the work andpull-back chambers of the press, and the operating device A serves as apilot valve for actuating the control valves B and C.

The control valves B and C may be of similar construction each, asshown, comprising a cylindrical casing in which a valve element isadapted to be moved endwise in one or the other direction by fluidpressure in opposed actuating cylinders or chambers, preferably atopposite ends of the valve casing. Referring first to main valve B, itscasing forms a central valve chamber l6 and opposite end actuatingcylinders I1 and i8, and its movable element comprises a body l9 havingspaced lands or enlarged portions 2|] and 20a slidably fitting in thevalve chamber l6, a'reduced central or waist portion and pistons 2| and22 at its opposite ends, one piston 2l working in the cylinder i1 andthe other piston .working in the cylinder l8. Pistons 2i and 22 are ofdifferent cross sectional areas, the piston 2| being the larger, so thatthe pressure on this piston can move the valve element to the right, asseen in the drawing, in opposition to pressure on the other piston. Theauxiliary control valve C is similar to the valve B, as thus fardescribed, and the corresponding parts are designated by the likereference numerals.

As illustrated, the operating valve A comprises a cylindrical casing23in which a movable element, comprising spaced pistons or lands 24 and 26on a rod or stem, is movable endwise, the rod or stem 28 projecting outof one end of the cylinder to enable actuation of the valve, as by meansof a foot pedal or member 2i which when 1 depressed, pushes the movableelement inwardly or in one direction, while opposite movement of theelement may be efiected as by a spring 28, located between the inner endof the movable element and the adjacent end of the valve casing. Anintermediate port in the casing of operating valve A is connected by apipe or conduit 30 with the accumulator, and said valve casing hasports, one connected by a pipe 3| and branches to the actuatingcylinders ll of the main and auxiliary control valves B and C, and theother connected by a pipe or conduit 32 and branches to-the opposedactuating cylinder ll! of the control valves B and C. Said pipe orconduit 3| also connects with the work chamber l2 of the press cylinder.Main control valve B has an intermediate port connecting by a pipe orconduit 35 with the aca chamber port of auxiliary valve C, and thechamber of auxiliary valve C has an intermediate port connected by apipe or conduit 38 with the pull-back chamber I3 of the press, andanother intermediate port connected by a pipe or conduit 39 with thework chamber |2 of the press, as by juncture with the pipe 36. Anexhaust pipe or conduit 40 is also connected by branches with theopposite ends of the chamber l6 of the main valve B, and by branches 4|and 42 with opposite end portions of the casing of the operating valveA.

In the pipe 3|, between its connections with the two control valves Band C, is a check valve 45 adapted to open freely, as indicated by thearrow, in the direction to admit pressure to the actuating cylinder I!of the auxiliary valve C. A bypass bleeder passage 46 permits slowleakage or only a restricted passage of pressure liquid through pipe 3|in the opposite direction past this check valve 45 when closed. In thesame pipe 3|, between its connections with the press chamber l2 and theauxiliary control valve is a check valve 41 adapted to open freely, asshown by the arrow, in the direction to admit passage of pressure fromthe work chamber |2 of the press cylinder; and also in the sameportionof pipe 3| is a pressure relief valve or device 43 of any'usual orsuitable construction adapted to open to permit passage of pressurefluid from the work chamber l2 of the press to the actuating cylinder I!of the auxiliary control valve 0 when the pressure in work chamber 2reaches a predetermined value for which the ressure relief valve 48 isset.

The operation of the press operating or con trol-mechanism may bedescribed as follows: The drawing shows by solid lines the positions ofthe movable parts of the mechanism when operating valve A has beenactuated by depression of its pedal 21 to start the work stroke of thepress ram or member. In this position of the operat'-- ing valve A,liquid is delivered from the accumulatqr through pipe 30, operatingvalve casing 23 and pipe 32 to the smaller actuating cylinders I8 of thetwo control valves B and C, thereby moving and holding their movableelements to the left, as shown in the drawing. Any opposing liquidpressure in the other valve actuating cylinders I! can exhaust throughpipe 3|, bleeder bypass 46, operating valve casing 23 and exhaust pipe42, thus permitting the left hand movement of the control valves B andC. Pressure liquid then will be delivered from the accumulator throughPipe 35, casing of main control valve B and pipe 36 to the work chamber|2 of the press to produce a working stroke of the Press raih or member.At this time, pipes 38 and 39 and the chamber of the auxiliary valve Cconnect the pull-back and'work chambers l3 and I2 of the press so thatliquid can flow freely from the pull-back chamber into the work chamber,thus producing rapid motion of the press piston member in its workingstroke. The free flow of the liquid from the pull-back chamber into thework chamber of the press in this way reduces the volume of pressureliquid required to be supplied by the accumulator to produce the workingstroke of the press ram and effects a rapid movement of the latter.When, because of increasing resistance of the work to this work strokeof the press ram or member, the liquid pressure in work chamber I2reaches the value for which the pressure relief valve 48 is set, thisvalve is opened by the liquid pressure from the work chamber I2 and theliquid will flow past the check valve 4'! and pressure relief valve 48into the actuating cylinder ll of auxiliary valve 0. Since the piston 2|is of larger diameter than the opposing piston 22, the movable elementof auxiliary valve C will be moved to the right, as seen in thedrawings, to the position indicated by the broken lines. Similaractuation of the main control valve B at this time by the pressure fromthe work cham-. ber l2 of the press is prevented because the cylinder llof main valve B is open to exhaust beyond the check valve 45 and bleederbypass 46, and main control valve B will remain in the left handposition shown. In this position of the two valves, the liquid willcontinue to pass from the accumulator to the work chamber |2 of thepress through the pipes 35 and 36, as before, but the liquid willdischarge from the pull-back chamber 3 through pipe 38, chamber l6 ofauxiliary valve C, pipe 31 and chamber of valve B to the exhaust pipe 40through its branch which connects with the right hand end of controlvalve B. Full pressure is thus applied to the press ram member to permitthe maximum pressure thereof on the work.

When the working stroke of the press ram has been completed, the pedal21 is released to permit the operating valve element to be moved by itsspring to its other Or left hand position, indicated by broken lines inthe drawing. In this position, operating valve will cut oil? the supplyof liquid from the accumulator through pipes 30 and 32 to the right handcylinders of control valves B and C and will connect supply pipe 30 withpipe 3|, thus delivering the pressure liquid to the left hand cylinderI! of the main control valve B and shifting the movable element of thisvalve to the position indicated by broken lines in the drawing. Theauxiliary control valve C had already been moved to this right handposition, as before explained, and is there held by admission ofpressure from the pipe 3| to the left hand cylinder ll of auxiliaryvalve C. In this position of the valves, work chamber l2 of the presswill be connected to the exhaust pipe 40 through pipe 36, chamber l6 ofmain valve B and the left hand branch of the exhaust pipe 40, whileliquid will be delivered from the accumulator through pipe 35, chamberl6 of main v'alve B, pipe 31, chamber of auxiliary valve 0. and pipe 38to the pullback chamber l3 of the press cylinder, thereby eifecting arapid return or movement to the left of the press ram or member. Theparts will remain in this position with the press ram in its retractedposition until the operating valve is again operated by depression ofits pedal to return the valves to the position shown by solid lines inthe drawings to effect the next operation of the press.

Upon such subsequent actuation of the operating valve, the pressureliquid will be admitted, as before explained, to the right handcylinders ll! of control valves B and C, and at this time the left handcylinder ll of the main valve B will be connected with the exhaust pipe40 through the pipe 3| and casing 23 of operating valve A and branch 42of exhaust pipe, and the left hand cylinder of the auxiliary controlvalve C will be similarly connected to the exhaust through pipe 3i andthe bleeder bypass 46 o! the check valve 45, which will thus permit thepressure on the smaller piston 22 of auxiliary valve C to overcome thepressure on the larger piston 2| thereof and thus restore this valve tothe solid line position shown, that is, to the left hand psition in thevalve casing, thus permitting the working stroke of the press ram asbefore explained.

I claim as my invention:

1. In an operating mechanism for an hydraulic press or the like having amovable member, a source of liquid under pressure, main and pullbackchambers, and means on which pressure liquid supplied to said chambersacts respectively to produce working and return strokes of said pressmember, the improved construction comprising a main valve having amovable element controlling ports and passages arranged to supply liquidfrom said supply source to said main press chamber and to exhaust liquidfrom said main and pull-back chambers, an auxiliary valvethaving amovable element controlling ports connecting with a port in the mainvalve and with said main and pull-back chambers, said main and auxiliaryvalves in a first position of their said elements I connecting said mainpress chamber with said supply source and connecting said pull-backchamber with said main chamber for effecting a rapid work stroke of thepress member, and said valves in said first position of said main valveelement and in a second position of said auxiliary valve elementconnecting said main chamber with said supply source and opening saidpull-back chamber to exhaust for increasing pressure on the pressmember, and said main and auxiliary valves in. the second position oftheir elements opening said main chamber to exhaust and connecting saidpull-back chamber with saidsupply source for returning said pressmember, first pressure actuated devices for moving said main andauxiliary valve elements to said first position and second pressureactuated devices for moving said main and auxiliary valve elements tosaid second position, an operating valve having a movable elementcontrolling ports and passages arranged to supply liquid from said saidsupply source to and exhaust liquid from said pressure actuated devicesfor said main and auxiliary valves, said passage to said second pressureactuating devices also connecting with said main press chamber, meanswhich controls saidpassage and allows flow of pressure liquid from saidmain press chamber to said'second actuating device of said auxiliaryvalve when the movable press member encounters a predeterminedresistance but prevents flow through said passage to said main chamber,and a check valve which controls said passage between said secondactuating devices for said main and auxiliary valves and allows ireeflow of liquid to the actuating device of said auxiliary 'valve and hasa bleeder bypass which allows restricted opposite flow of liquid.

2. In an operating mechanism for an hydraulic press or the like having amovable member, a source of liquid under pressure, main and pullbackchambers, and means on which pressure liquid supplied to said chambersa'cts respectively to produce working and return strokes of said pressmember, the improved construction comprising a main valve having amovable element controlling ports and passages arranged to supply liquidfrom said supply source to said main press chamber and to exhaust liquidfrom said main and pull-back chambers, an auxiliary valve haying amovable element controlling ports connecting .with a port in the mainvalve and with said main and pull-back chambers, said main and auxiliaryvalves in a first position of their said elements connecting said mainpress chamber with said supply source and connecting saidpull-back'chamber with said main chamber for effecting a rapid workstrok of the press member, and said valves in said first position ofsaid main valve element and in a second position of said auxiliary valveelement connecting said main chamber with said supply source and openingsaid pull-back chamber to exhaust for increasing pressure on the pressmember, and said main and auxiliary valves in the second position oftheir elements opening said main chamber to exhaust and connecting saidpull-back chamber with said supply source for returning said pressmember, first pressure actuated devices for moving said main andauxiliary valve elements to said first position and second pressureactuated devices for moving said main and auxiliary valve elements tosaid second position, an operating valve having a movable elementcontrolling ports and passages arranged to supply liquid from saidsupply source to and exhaust liquid from said pressure actuated devicesfor said main and auxiliary valves, said passages to said secondpressure actuating devices also connecting with said main press chamber,a check valve and a pres sure relief valve which control said passageand prevent liquid flow therethrough to said main press chamber butallow fiow of pressure liquid from the main press chamber to said secondactuating device of said auxiliary valve when the movable press memberencounters a predetermined resistance, and a check valve which controlssaid passage between said second actutaing devices for said main andauxiliaryvalves and allows free fiow of liquid to the actuating deviceof said auxiliary valve and has a bleeder bypass which allows restrictedopposite flow of liquid.

3. In an operating mechanism for an hydraulic press or the like having amovable member, a sourc of liquid under pressure, main and pullbackchambers, and means on which pressure liquid supplied to said chambersacts respectively to produce working and return strokesof said pressmember, the improved construction comprising main and auxiliary valveseach having a reciprocable element with. opposed actuating pistons ofdifferent pressure areas working in correspondingly different pressurecylinders, said main valve element controlling ports and passagesarranged to supply liquid from said supply source to said main presschamber and to exhaust liquid from said main and pull-back chambers, andsaid auxiliary valve element controlling ports connecting with a port inthe main valve and with said main and pull-back chambers, said main andauxiliary valves in a first position of their said elements connectingsaid main press chamber with said supply source and connecting saidpull-back chamber with said main chamber for effecting a rapid workstroke of the press memher, and said valves in'said first position-ofsaid,

main valve element and in a second position of said auxiliary valveelement connecting said main chamber with said supply source and openingsaid pull-back chamber to exhaust for increasing pressure on the pressmember, and said main and auxiliary valves in the second position oftheir said elements opening said main chamber ber with said supplysource for returning said press member, an operating valve and passagesconstructed and arranged to supply liquid from said source to andexhaust liquid from said actuating cylinders for moving said main andauxiliary valve elements to said first and second positions, saidpassage to the cylinders of larger area also connecting with said mainpress chamber, means which controls said passage and allows flow ofpressure liquid from said main press chamber to the actuating cylinderof said auxiliary valve when the movable press member encounters apredetermined resistance but prevents flow through said passage to themain press chamber, and a check valve which controls sai passage betweenits connections with the actuating cylinders for said main and auxiliaryvalves and allows free flow of liquid to the actuating cylinder of saidauxiliary valve and has a bleeder bypass which allows only restrictedopposite flow oi liquid.

4. In-an operating system for a fluid actuated operating said main valveto vent said advancing chamber and connect said source to said auxiliaryvalve, and for operating said auxiliary valve to break said directconnection between said chambers and connect sald'retracting chamber tosaid source through said main valve, and means automatically responsiveto fluid pressure in said advanein chamber for separately causingoperation or said auxiliary valve to break the direct connection betweensaid chambers whenever the fluid pressure in said advancing chamber isabove a predetermined pressure.

6. In an operating system for a fluid actuated motor of that type havingadvancing and retracting chambers, a working element operated bypressure alternately in said chambers, and a source of actuating fluidunder pressure, that improvement in the control of the movement of saidelement which comprises means for connecting said source alternately tosaid chambers and venting the chamber not connected to said source,

motor of the type having advancing and retracting chambers, a workingelement operated by pressure alternately in said chambers, and a sourceof actuating fluid under pressure, that improvement in the control ofthe movement of said element which comprises a main valve and anauxiliary valve each having two conditions of operation. and pilotcontrolled means for operating said valves into said conditions,connections by which said auxiliary valve when in one condition connectssaid chambers directly to each other and when in another conditiondisconnects said chambers from each other and connects said retractingchamber to said main valve, connections by whichsaid main valve when inone condition connects said source to said advancing chamber andconnects said auxiliary valve to exhaust, and in another conditionconnects said source to said auxiliary valve and connects said advancingchamber to exhaust, a control valve, and direct connections independentof said main and auxiliary valves between said source, said controlvalve and said pilot controlled means for causing operations of saidmain and auxiliary valves upon operation of said control valve, andmeans automatically responsive to the pressure in said advancing chamberfor causing operation of said auxiliary valve into its said anothercondition while the pressure in said advancing chamher is above apredetermined pressure.

5. In an operating system for a fluid actuated motor of the type havingadvancing and retracting chambers, a working element operated bypressure alternately in said chambers, and a source of actuating fluidunder pressure, that improvement in the control of the movement of saidelement which comprises a main valve, an auxiliary valve, connectionscontrolled by said auxiliary valve for alternately connecting saidchambers directly together, and for breaking said direct connections andconnectingsaid retracting chamber to said main valve, connectionscontrolled by said main valve for connecting said source alternately tosaid advancing chamber and to said auxiilary valve, and for venting anyconnections not connected to said source, a control valve, meanscontrolled by said control valve and operating independently of saidmain and auxiliary valves for either causing operation of said mainvalve to connect said source to said advancing chamber and operation orsaid auxiliary valve to connect said chambers directly, or for means forbreaking the connection from said source to said retracting chamber andinstead connecting said retracting chamber directly to said advancingchamber, selectively controlled means operating independently of saidfirst and second mentioned means to cause operation of said first meansto connect said source to said advancing chamber and concurrently ofsaid second means to directly connect said chambers, or to causeoperation of said first means to vent the connection to said advancingchamber and connect said source through said first means to saidretracting chamber, and means responsive to the fluid pressure in saidadvancing chamber and free of the control of said controlled means, for

. forcibly operating said second means to break the fluid supplied tosaid chambers acts respectively to produce working and return strokes ofsaid motor member, the improved construction comprising a main valvehaving a movable element controlling ports and passages arranged tosupply fluid from said supply source to said main chamber and to exhaustliquid from said main and pull-back chambers, an auxiliary valve havinga movable element controlling ports connecting with a port in the mainvalve and with said main and pull-back chambers, said main and auxiliaryvalves in a first position of their said elements connecting said mainpress chamber with said supply source and connecting said pullbackchamber with said -main chamber for effecting a rapid work stroke of themotor mem ber, and said valves in said first position of said main valveelement and in a second position of said auxiliary valve elementconnecting said main said first and last mentioned relative positions,and means actuated under control or fluid pressure from said mainchamber when the movable motor member encounters a predeterminedresistance for effecting said second mentioned relative positions orsaid main and auxiliary valve elements.

8. In an operating mechanism for a fluid actuated motor having a movablemember, a source of fluid under pressure, main and pull-back chambers,and means on which pressure fluid supplied to said chambers actsrepectively to produce working and return strokes of said motor member,the improved construction comprising a main valve having a movableelement controlling ports and passages arranged to supply fluid fromsaid supply source to said main chamber and to exhaust fluid from saidmain and pull-back chambers, an auxiliary valve having a movable elementcontrolling ports connecting with a port in the main valve and with saidmain and pull-back chambers, said main and auxiliary valves in a firstposition of their said elements connecting said main chamber with saidsupply source and connecting said pull-back chamber with said mainchamber for eifecting a rapid work stroke of the motor member, and saidvalves in said first posi tion of said main valve element and in asecond position of said auxiliary valve element connecting said mainchamber with said supply source and opening said pull-back chamber toexhaust for increasing pressure on'the motor member, and

said main and auxiliary valves in the second position of their elementsopening said main chamber to exhaust and connecting said pull-backchamber with said supply source for returning said motor member, firstpressure actuated devices for moving said main and auxiliary valveelements to said first position and second pressure actuated devices formoving said main and auxiliary valve elements to said second position,

an operating valve having a movable element movable motor memberencounters a predetermined resistance but prevents flow through saidpassage to said main chamber, and means which controls said passagebetween said second actuating devices for said mainand auxiliary valvesand allows free flow of fluid to the actuating device of said auxiliaryvalve and allows only restricted opposite'flow of fluid.

THOMAS F. STACY;

